Specifies how the virtual machine should be created.
Possible values are:
Attach \u2013 This value is used when you are using a specialized disk to create the virtual machine.
FromImage \u2013 This value is used when you are using an image to create the virtual machine. If you are using a platform image, you also use the imageReference element described above. If you are using a marketplace image, you also use the plan element previously described.
